‘Oumuamua: New Work on Interstellar Objects

byPaul GilsteronFebruary 14, 2018

Anomalous objects are a problem — we need more than one to figure them out. One ‘hot Jupiter’ could have been an extreme anomaly, but we went on to find enough of them to realize this was a kind of planet that had a place in our catalog. Or think of those two Kuiper Belt objects that New Horizons imaged, as discussed in yesterday’s post. Soon we’ll have much closer imagery of MU69, but it will take more encounters — and more spacecraft — to begin to fathom the full range of objects that make up the Kuiper Belt. Ultimately, we’d like to see enough KBOs up close to start drawing statistically valid conclusions about the entire population.

So where does the intriguing ‘Oumuamua fit into all this? It was the first interstellar asteroid we’ve been able to look at, even if the encounter was fleeting. A friend asked me, having learned of the Breakthrough Listen SETI monitoring of the object, whether it wasn’t absurd to imagine it could be a craft from another civilization. I could only say that the idea was highly unlikely, but given how little time we had and how rare the object was, how could we not have listened? I favor throwing whatever resources we have at an opportunity this unusual.

And time was short, as Joshua Sokol recently noted in Scientific American. We found ‘Oumuamua in late October of last year, but getting a probe to it on the best possible trajectory would have demanded a launch the previous July. I see that Greg Laughlin (UC-Santa Cruz), working with Yale doctoral student Darryl Seligman, has been exploring how we might drive an impactor into a future interstellar visitor, allowing the kind of analysis we did with the Deep Impact mission. I’ll have more on the idea as the paper wends its way through peer review.

Image: This animation shows the path of ‘Oumuamua, which passed through our inner solar system in September and October 2017. From analysis of its motion, scientists calculate that it probably originated from outside of our Solar System. Credit: NASA/JPL-Caltech.

We appear to be getting into the era of comparative interstellar object studies. One, two, many ‘Oumuamuas, not to mention their cousins, who may not just pass through but stick around. Harvard’s Avi Loeb, working with Manasvi Lingam (Harvard-Smithsonian Center for Astrophysics), offers a paper on ‘Oumuamua that’s now available on the arXiv server. Here we get a sense of the broader population of interstellar objects, not all of which may have departed.

The authors have approached the question by asking how likely it is for interstellar objects to be captured in our Solar System, performing the same kind of analysis for the Alpha Centauri system. The scientists believe several thousand captured interstellar objects may be within the Solar System at any given time, with the largest of these reaching tens of kilometers in size.

‘Oumuamua came and went quickly, but a long-lingering population offers us ample grounds for investigation. Likening the effects of the Sun and Jupiter to a fishing net, the authors peg the number of interstellar objects currently within the system at ~ 6 x 103, pointing out that they offer us the potential to study exoplanetary debris without leaving our own system.

But how to determine whether an object now bound to our Solar System really is interstellar in origin? The answer may lie in the chemical constitution of water vapor found associated with the object. The oxygen isotope ratios may hold the key, as the paper explains:

…if the oxygen isotope ratios are markedly different from the values commonly observed in the Solar system, it may suggest that the object is interstellar in nature; more specifically, the ratio of 17O/18O is distinctly lower for the Solar system compared to the Galactic value (Nittler & Gaidos 2012), and hence a higher value of this ratio may be suggestive of interstellar origin.

To make this work, we could analyze these isotopes through high-resolution spectroscopy, working in the optical, infrared and submillimeter ranges of water vapor in cometary tails, just as the Herschel observatory was able to measure the isotope ratio of comet C/2009 P1 in the Oort cloud. A flyby and perhaps even a sample return mission could not be ruled out either, with the interesting implication that a technology like Breakthrough Starshot’s could be used to explore much closer targets than Proxima Centauri with short mission times.

But if thousands of interstellar objects are within our Solar System now, what implications does this offer for the emergence of life? The paper notes that some 400 interstellar objects with a radius in the 0.1 kilometer range could have struck the Earth prior to abiogenesis, and about 10 could have been kilometer-sized. The possibility of interstellar panspermia is evident. The paper continues:

If a km-sized interstellar object were to strike the Earth, we suggested that it would result in pronounced local changes, although the global effects may be transient. Habitable planets could have been seeded by means of panspermia through two different channels: (i) direct impact of interstellar objects, and (ii) temporary capture of the interstellar object followed by interplanetary panspermia. There are multiple uncertainties involved in all panspermia models, as the probability of alien microbes surviving ejection, transit and reentry remains poorly constrained despite recent advancements.

It’s interesting to note on this score that while the Solar System might have snared objects up to tens of kilometers in size, the Alpha Centauri system could capture objects up to Earth size, making for the possibility of a life-bearing world being acquired in its entirety.

‘Oumuamua work continues in a letter from Carlos de la Fuente Marcos (Complutense University of Madrid) that analyzes the orbits of 339 known hyperbolic objects and models their histories, finding eight possible interstellar objects within past astronomical observations. Unlike Loeb and Lingam’s population of captured objects, these visitors followed the ‘Oumuamua model, making a single brief appearance, but they offer the possibility that our archives contain further examples of such wanderers. The onset of observations with the Large Synoptic Survey Telescope in the early 2020s may help us further constrain the population of unbound objects.

The paper is Lingam & Loeb, “Implications of Captured Interstellar Objects for Panspermia and Extraterrestrial Life” (preprint). The de la Fuente Marcos paper is “Where the Solar system meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies,” Monthly Notices of the Royal Astronomical Society 20 February 2018 (abstract).

I was surprised to read in another venue that listening for radio signals was about all that was done to determine if ‘Oumuamua might have been an alien ship. To assume it would be transmitting in radio frequencies was rather strange.

Hitting an interstellar object with a penetrator :- I would hope that we determine that such an object is natural first, otherwise that could be considered “enemy action”.

Panspermia :- I think we might need to start taking this idea more seriously. All asteroid or comet objects should have some sort of life investigation applied to determine if they harbor life in any form – whether active or as spores. I don’t know how this might be done on a cost effective and reliable basis, but if we found solar system objects harboring a thin skein of life that was viable, perhaps from Earth, then we should definitely apply those techniques to interstellar objects as we could assume that they might also harbor life from a living planet in their solar system of origin.

Yes, remember what happened after the Enterprise destroyed Balok’s increasingly radiation-emitting space buoy in “The Corbomite Maneuver.” :-) Not only would a penetrator impact on a seemingly-derelict (but merely quiet) interstellar probe or ship look just like a hostile act, but a sufficiently small and/or fragile *natural* interstellar object could be broken up by a penetrator. Also:

In Chapter 15 of his book, “Fly Me to the Moon: An Insider’s Guide to the New Science of Space Travel,” Edward Belbruno (the mathematician who pioneered the use of WSB–Weak Stability Boundary–low-energy transfer trajectories for spacecraft, which he found to also occur among natural celestial bodies, including “orbital resonance-hopping” comets) discussed WSB trajectories between stars, including those in open star clusters. He found that inward-falling comets that are ejected back out to the Oort Cloud (~100,000 A.U. out) in elliptical orbits can easily find themselves–once out there–perturbed into parabolic and then slightly hyperbolic solar system escape trajectories, and:

Those which escape in the direction of the Alpha Centauri system can make the crossing in just 645,000 years, an astronomically & geologically short period of time. This implies, as he wrote, that in open star clusters (whose member stars often have even lower relative velocities with respect to each other [about 1 kilometer per second] than that between our Sun and the Alpha Centauri stars), comets can be transferred between their stars, with all that this implies for the spread of water and organic materials between suitably “receptive” terrestrial-type exoplanets. (It might not be strange, if life forms found throughout a given star cluster were rather similar to each other.)

Trying to hit an object could also be a way to test if it is artificial. If it moves to avoid the projectile then its artificial nature is confirmed. Obviously, we should try every other test first, but I don’t think we should rule out a test that could be interpreted as ‘firing a shot across the bow’. If an ETI visitor doesn’t respond to radio or optical signals and is on an intercept course for Earth or other important solar system assets, then shooting at it would, arguably, be rationale.

I wish all sides of SETI and METI would come together, be willing to be shown wrong, and develop action plans for how to engage an ETI visitor.

If these objects are protected by coatings or other natural material that protects and keeps viruses or other biological entities healthy, hitting it with a projectile could release pathogens. The 1918 Influenza Pandemic was eight years after Halley’s Comet tail brushed the Earth in 1910. Just imagine what parasitic viruses could come from an object from another solar system!

How many meter size or smaller objects from outside the solar system hit the Earth daily? What about meteor showers from a galactic object that that broke up after coming into orbit around the sun? Could some of the mass extinctions have been caused by viruses traveling on parts ejected from other planets in our galaxy? Could the Earth and solar system encounter more of these objects when the Sun passes thru the galactic arms of the Milky Way?

Surprising that just a hundred years ago the Sun was still considered to be at the center of our galaxy. In 1918 Harlow Shapley realized that the sun was on the outskirts of the Milky Way. In 1912, Vesto Slipher was the first to observe the shift of spectral lines of galaxies, making him the discoverer of galactic redshifts. In 1914, Slipher also made the first discovery of the rotation of spiral galaxies at the Lowell Observatory in Flagstaff, Arizona. Edwin Hubble is often incorrectly credited with discovering the redshift of galaxies; these measurements and their significance were understood before 1917 by James Edward Keeler (Lick & Allegheny), Vesto Melvin Slipher (Lowell), and William Wallace Campbell (Lick) at other observatories.

Panspermia and the Origin of Life on Earth.

Panspermia is a Greek word that translates literally as “seeds everywhere”. The panspermia hypothesis states that the “seeds” of life exist all over the Universe and can be propagated through space from one location to another. Some believe that life on Earth may have originated through these “seeds”.

History of Panspermia.

The first known mention of the concept of panspermia was in the writings of the Greek philosopher Anaxagoras (500 BC – 428 BC), although his concept differs from the modern theory:

All things have existed from the beginning. But originally they existed in infinitesimally small fragments of themselves, endless in number and inextricably combined. All things existed in this mass, but in a confused and indistinguishable form. There were the seeds (spermata) or miniatures of wheat and flesh and gold in the primitive mixture; but these parts, of like nature with their wholes, had to be eliminated from the complex mass before they could receive a definite name and character.

In 1743 the theory of panspermia appeared in the writings of French nobleman, diplomat and natural historian Benoît de Maillet, who believed that that life on Earth was “seeded” by germs from space falling into the oceans, rather than life arising through abiogenesis.

The panspermia theory was rekindled in the nineteenth century by the scientists Jöns Jacob Berzelius (1779–1848), Lord Kelvin (William Thomson) (1824–1907) and Hermann von Helmholtz (1821–1894). Lord Kelvin declared in 1871, “[W]e must regard it as probable in the highest degree that there are countless seed-bearing meteoric stones moving about through space. If at the present instance no life existed upon this Earth, one such stone falling upon it might, by what we blindly call natural causes, lead to its becoming covered with vegetation.”

In 1973 the late Nobel prize winning British molecular biologist, physicist and neuroscientist Professor Francis Crick, along with British chemist Leslie Orgel, proposed the theory of directed panspermia.

It is time to realize that life in the universe may survive and thrive on any planet that has that correct conditions to sustain it. The idea that earth is the center of the universe and also life in the universe needs to be questioned. Panspermia is like the The Copernican concept for biological life.

Maybe the reason that Saturn is so puffed up is because it has a bad yeast infection. :-)

I believe we should remind ourselves about what The Scientific Method has to say about conclusions reached from the evidence of one single event ….as long as Earth -life is a single event , absolutely nothing can be known about the probabaility of life elsewhere , exept for the obvious fact that this probabality is bigger than zero

I apologize if this comes across as uncivil, but I think you present a caricature of the scientific method. According to the SM, reality is reproducible because the laws governing the processes that build reality are universal. If an experiment delivers a result that can never be reproduced, then the original result/interpretation never happened. The SM abhors the non-reproducible. Life on Earth happened, humanity happened. A non-zero chance is something and we can use the complexity of the process for abiogenesis and evolution on Earth to extrapolate the likelihood that life arose and evolved elsewhere.

The entire path for abiogenesis and the evolution of human type intelligence may be the longest and most narrow path that the galaxy or the universe can provide. However, when we make the argument that the path is so long and narrow, we need to remember that with only a change of perspective that path becomes the tallest pedestal. We refuse to put ‘Oumuamua or any other naturally occurring phenomena on a pedestal and should be wary of putting ourselves on one.

Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, h.

(Submitted on 14 Feb 2018)
“The TRAPPIST-1 system is unique in that it has a chain of seven terrestrial Earth-like planets located close to or in its habitable zone. In this paper, we study the effect of potential cometary impacts on the TRAPPIST-1 planets and how they would affect the primordial atmospheres of these planets. We consider both atmospheric mass loss and volatile delivery with a view to assessing whether any sort of life has a chance to develop. We ran N-body simulations to investigate the orbital evolution of potential impacting comets, to determine which planets are more likely to be impacted and the distributions of impact velocities. We consider three scenarios that could potentially throw comets into the inner region (i.e within 0.1au where the seven planets are located) from an (as yet undetected) outer belt similar to the Kuiper belt or an Oort cloud: Planet scattering, the Kozai-Lidov mechanism and Galactic tides. For the different scenarios, we quantify, for each planet, how much atmospheric mass is lost and what mass of volatiles can be delivered over the age of the system depending on the mass scattered out of the outer belt. We find that the resulting high velocity impacts can easily destroy the primordial atmospheres of all seven planets, even if the mass scattered from the outer belt is as low as that of the Kuiper belt. However, we find that the atmospheres of the outermost planets f, g and h can also easily be replenished with cometary volatiles (e.g. ∼ an Earth ocean mass of water could be delivered). These scenarios would thus imply that the atmospheres of these outermost planets could be more massive than those of the innermost planets, and have volatiles-enriched composition.”

The evolutionary history of viruses represents a fascinating, albeit murky, topic for virologists and cell biologists. Because of the great diversity among viruses, biologists have struggled with how to classify these entities and how to relate them to the conventional tree of life. They may represent genetic elements that gained the ability to move between cells. They may represent previously free-living organisms that became parasites. They may be the precursors of life as we know it.

“A cell is an independent living entity that can eat, grow and reproduce. Unicellular bacteria are not much different from human or mammalian cells with regards to their complex cellular make up and processes though much smaller in size. A virus, on the other hand, is a simpler form of life and resembles no similarity to living cells. Viruses are not classified as typical living cells. Rather a virus is a piece of genetic information (DNA or RNA) within a protective coat. They lack all the machinery a cell possesses to survive and replicate, other than a small quantity of DNA or RNA. Viruses transform into living particles only when inside their particular host cells being able to metabolize and reproduce. Once outside their host cells, they are just a non-living complex molecular particle that have no metabolic activities and no way to reproduce. Due to these characteristics viruses were thought to be the pre-cellular life forms that link non-living materials with living beings. Though this notion has fallen apart, the viruses are still believed as one of the most ancient forms of life. Around 4,000 different types of viruses have been characterized which is just a tiny fraction of the total number of types of viruses present on Earth. Having no independent metabolism and reproductive machinery, they can remain viable in a dormant state outside their host cells for indefinite periods of time under the right circumstances. Some of the viruses can even be crystallized like minerals in their non-living state. In this state the viruses can survive for millions of years unchanged until they are come in contact with moisture and their particular hosts. Inside the right host cell and with favourable conditions, the dormant viruses can become active and begin to metabolize and reproduce [19,20]. These characteristics of a virus makes it a perfect candidate for travel through space inside the protective shields of comets or meteoroids. As it is well known that amorphous ice is abundant in the depths of interstellar medium [21], the virus might also get trapped in the amorphous ice inside comets or asteroids and spread life in a planet that offers a host with a favourable condition for life to survive and replicate.”

“The extraordinary role of viruses in evolution and how this is revolutionising biology and medicine.Darwin’s theory of evolution is still the greatest breakthrough in biological science. His explanation of the role of natural selection in driving the evolution of life on earth depended on steady variation of living things over time – but he was unable to explain how this variation occurred. In the 150 years since publication of the Origin of Species, we have discovered three main sources for this variation – mutation, hybridisation and epigenetics. Then on Sunday, 12th February, 2001 the evidence for perhaps the most extraordinary cause of variation was simultaneously released by two organisations – the code for the entire human genome. Not only was the human genome unbelievably simple (it is only ten times more complicated than a bacteria), but embedded in the code were large fragments that were derived from viruses – fragments that were vital to evolution of all organisms and the evidence for a fourth and vital source of variation – viruses.Virolution is the product of Dr Frank Ryan’s decade of research at the frontiers of this new science – now called viral symbiosis – and the amazing revolution that it has had in these few years. As scientists begin to look for evidence of viral involvement in more and more processes, they have discovered that they are vital in nearly every case. And with this understanding comes the possibility of manipulating the role of the viruses to help fight a huge range of diseases.”

“The past year has been one of viral panic-panic about viruses, that is. Through headlines, public health warnings, and at least one homemade hazmat suit, we were reminded of the powerful force of viruses. They are the smallest living things known to science, yet they can hold the entire planet in their sway. A Planet of Viruses is Carl Zimmer’s eye-opening look at the hidden world of viruses. Zimmer, the popular science writer and author of National Geographic’s award-winning blog The Loom, has updated this edition to include the stories of new outbreaks, such as Ebola, MERS, and chikungunya virus; new scientific discoveries, such as a hundred-million-year-old virus that infected the common ancestor of armadillos, elephants, and humans; and new findings that show why climate change may lead to even deadlier outbreaks. Zimmer’s lucid explanations and fascinating stories demonstrate how deeply humans and viruses are intertwined. Viruses helped give rise to the first life-forms, are responsible for many of our most devastating diseases, and will continue to control our fate for centuries.”

“Dr. Albert Erives, a biologist at the University of Iowa, has identified a virus family whose set of genes is similar to that of eukaryotes, an organism classification that includes all plants and animals. The finding is important because it helps clarify how eukaryotes evolved after branching from prokaryotes (single-celled organisms) about two billion years ago.”

Viruses are the most abundant and one of the least understood biological entities on modern Earth. They might also exist in space, but as of yet scientists have done almost no research into this possibility. Portland State University’s Professor Ken Stedman and co-authors hope to inspire integration of virus research into astrobiology.

Berliner et al review current virology research pertinent to astrobiology and propose ideas for future astrovirology research foci. Viruses are an integral, highly abundant yet underappreciated part of life on Earth. They are highly diverse both in structure and genomic sequence, play a critical role in biogeochemical cycles and evolution. However, there is yet very little focus on viruses in astrobiology.

Professor Stedman and his colleagues from the University of California, Berkeley, and Tokyo Institute of Technology are trying to change this through their article published in the February issue of the journal Astrobiology.

“More than a century has passed since the discovery of the first viruses,” Professor Stedman said. “Entering the second century of virology, we can finally start focusing beyond our own planet.”

“Virions — the extracellular form of viruses — are the most abundant biological particles on Earth, with an estimated 1031 virions in the oceans alone,” the scientists said. “Whether this amazing virion abundance is true in extraterrestrial oceans or was true in primordial Earth oceans are open questions.”

In their call to arms, the researchers state that NASA and other space agencies should be looking for viruses in liquid samples from Saturn and Jupiter’s moons, develop technology to detect viruses in ancient deposits on Earth and Mars, and determine if Earth viruses could survive in space.

They explained: “priorities for future astrovirology research in the short term should include:

(i) validation of virus biosignatures;

(ii) consideration of virus-detection experiments to be used for missions that sample water plumes from Enceladus and Europa;

(iii) inclusion of viruses in models for ancient oceans and extraterrestrial systems;

This matter-of-fact heading comes in a well-referenced review article by three expert virologists. They confirm this once-radical notion with accumulated knowledge that needs to be more widely recognized. For example, …the successful transfer of novel viral genes into host genomes is likely commonplace. …the human genome contains between 8% and 40% virus derived sequences, some of which have been beneficial for human development. (Recognized protein-coding genes occupy c. 2% of the human genome.)
They also remind us that viral genes are mostly unknown. Many viral genomes contain genes that have no homologs except in closely related viruses. …A recent analysis of all published viral DNA metagenomes found that nearly 70% of virus-associated genes were novel. We think viral genes might enable future life here to evolve in unforseeable ways.

The problem with viruses as interstellar travelers is with their need to use the host’s molecular biology. For example, even if the virus had exactly the same DNA structure and bases as terrestrial organisms, if it uses a different genetic code, the proteins for its coat would be translated incorrectly, making the virus a poor vector. If its DNA was in any way different, or the proteins used a different set of amino acids, they would be useless carriers of DNA. This is not a problem for other organisms that can build up their components from simpler, universal elements and compounds.

Conversely, should it be found that an interstellar virus could successfully be replicated by a terrestrial host, then that would imply that life uses the same biology across stellar systems. That may say something about abiogenesis or that panspermia by other organisms is common so that life has a common cosmic ancestor.

Alex, a very fascinating subject and one that is just starting to be understood. Can we tell if a virus is completely alien to viruses that exist on earth? The example that we need to be able to distinguish is on places such as the moons of Jupiter , Saturn, and also comets. Would there be telltale signs that would be easy to identify alien viruses from possible viruses that traveled from earth on the solar winds to those objects and evolved in that environment? What about on earth with all the many viruses, could we figure out if a virus had come from someplace else? Would the study of such things even look for such novel vector viruses? I’m sure that the military biological warfare would have information relating to this, so somewhere deep down in the earth maybe they have viruses from Andromeda!

Could early ETC have realized that the biological DNA was the best way to populate the universe or galaxy and used the viruses to help evolution create intelligent species?

“Can we tell if a virus is completely alien to viruses that exist on earth?”

The first problem is that if their genetic code is different, they will not reproduce, so they will be vanishingly rare. But let us suppose there are also alien bacteria that alien phage viruses can “predate” upon. In that case, we could separate them from terrestrial viruses by determining that reproduction of their protein coats will fail in terrestrial hosts or artificial conditions that require our terrestrial genetic code. That is one way. So we could imagine a spacecraft that captures some viruses from an interstellar object. We can decode its DNA sequence. But while the DNA replicates, no viral particles are produced because the proteins will not form the coat.

If the DNA uses different bases or architecture, e.g. doesn’t have the same sugar-phosphate backbone, or a different twist in the double helix, then we could detect this with a variety of techniques, IF we have sensitive enough equipment or some other way to replicate the viral sample.
That would be very challenging, but we are making a lot of progress on this front, so certainly possible in the future.

Alex, in the normal environment live viruses dominated our existence, but what if there is a location where they are preserved in a pristine condition. The ice cores from Antarctica would have viruses entombed in them from millions of years, this could give us a sample of alien origin and also show the changes that have taken place for earthy viruses.

Though it is hanging by the proverbial thread now, the possibility that `Oumuamua is not a natural object is not dead yet. Here’s the reasoning. Unlike a previous paper claiming that `Oumuamua was COMPLETELY COVERED in a tar-like substance that COMPLETELY SHIELDED it from the heat it incurred from its close passage to the Sun, a more recent paper argues that ONLY ONE “END” of `Oumuamua is red, whereas the great majority of it is a very neutral grey! This means there are probably very different compositions to the different components. The only natural explanation for this is that, in its home star system, `Oumuamua was subjected to two SEPARATE EVENTS. Event number one: A “soft” collision between an asteroid(grey) and a comet(red), which caused the “new” object to start tumbling. Event number two: Close passage to a gas-giant planet or brown dwarf AFTER event number one. Now, here’s the problem with all of this: A soft collision by any two kinds of bodies would NOT create a strong bonding between the pair, and the bond would probably be even WEAKER(speculative) between an asteriod and a comet. The stress put on it by tumbling would weaken the bond EVEN MORE! Then, at perihelion, the ADDED heat(affecting the asteroid and the comet DIFFERENTLY)COMBINED with angular momentum stress would ALMOST CERTAINLY TEAR `OUMUAMUA APART at the junction between the asteroid and the comet. Finally, NOT ONE SINGLE PAPER has come out involving observations made by HST and Spitzer. What is taking them so long?

Actually, only six weeks for HST. The LAST `Oumuamua image HST took was on January2, as part of a campaign to PINPOINT the trajectory. The CURRENT trajectory indicates a ratio of closest SUN distance to closest EARTH distance that is VERY close to the value of phi, the golden ratio number. If there are any MINUTE REVISIONS due to the BETTER HST data, and this ratio DOES become phi, to say; eight decimal points, it would STRONGLY indicate that `Oumuamua DID send us a message, As for Spitzer, a paper could have been submitted WEEKS ago to either the journals “Nature” or “Science”, and due to their policies, NOT BE MADE PUBLIC on ArXiv. This would be ESPECIALLY the case if the paper was under EMBARGO to to an EXTRAORDINARY claim!

If there are thousands of interstellar objects in the outer solar system, a probe that does not call attention to itself would be almost impossible to find–particularly if it looks like Oumuamua. I wonder how close to the planetary system such a probe must be to make useful observations.

This is very interesting!
That objects from other stars might hide in the solar system is not completely surprising, even so it give a chance to make up for the lost opportunity of Oumuamua.
More surprising is that a planet could get caught by the Alpha Centauri group of stars.
But yes, I understand it can happen in a cosmic billiard game.
Planets without a star have been identified, so this increase the chance that even stars that were not the best enviroment later can catch stars.
It would only be a matter of time, and time is very much available when we talk about cosmos! :)

The talk of radio signals, and Oumuamua as alien spacecraft – please be serious. Enough of such in stupid newspapers and youtube. :(

Andrei, I think speculation about ‘Oumuamua possibly being an alien spacecraft is perfectly serious (I think it is most likely an entirely natural object, but we never got a close enough look at it to be certain), for several reasons:

For relatively slow interstellar transits, asteroids have been written about–including in the Journal of the British Interplanetary Society, by serious researchers–as possible DIY (“Do It Yourself”) starships, because they would provide excellent protection against radiation and particle impacts for the crew and equipment located inside, without having to launch such masses of shielding material from the Earth. (Modified carbonaceous asteroids have also been suggested by planetary scientist Dr. John S. Lewis for use as Earth-Mars and intra-asteroid belt cycling spacecraft, due to their excellent radiation shielding capabilities.) Also:

While this powered asteroid interstellar spacecraft concept has been considered mostly in connection with “slow boat” interstellar colonization missions, the radiation and impact protections provided by this “asteroid dugout canoe” approach would also be useful to automated spacecraft. It would enable essentially immortal starprobes to travel from star to star via stellar gravity assists, and:

The colors of ‘Oumuamua that Harry R Ray mentioned above (neutral gray overall, and “cometary tar [tholins] red” on one end) are what one might expect for an ‘asteroid-sheathed’ starprobe or starship. The cometary ‘tar’ could serve as a natural, in-space-sourced radiation and erosion shield (similar in function to the beryllium erosion shield proposed for the Daedalus starprobe). ‘Oumuamua’s tumble could have been deliberate, serving as a means of scanning fixed instruments all around the celestial sphere, although–if ‘Oumuamua *is* a modified asteroid containing a probe–the tumble could indicate that it became inoperative long ago. In addition:

While I believe that the simplest, most prosaic explanation for ‘Oumuamua’s origin and nature–that it’s a naturally gravitationally ejected, natural interstellar asteroid–is the correct one, we can’t be 100% certain, because it never came close enough for us to tell. If other interstellar objects like ‘Oumuamua *aren’t* seen in the future (some astronomers think they are so common that at least one such object may pass through our solar system each year), such an outcome might, ironically, strengthen the potential case for ‘Oumuamua having been more than met the eye.

How hard would it really be to hide an alien probe from humanity if an ETI sent one to our system to monitor us? I would say not very difficult now and even easier to do so in the past.

Between our lack of knowledge on the subject and the unwillingness of many, especially the professional scientists, to acknowledge such a thing, an ETI hiding from us in our own backyard (or right in our home, Earth) would find themselves with a variety of method to remain incognito from human scrutiny.

While ‘Oumuamua is very likely anything but artificial, if it had been made by alien minds and appendages, the fact that it zipped past us without stopping or even slowing down says the following if it is artificial:

1. The probe stopped functioning a while ago and only momentum has kept it going.

2. It was only designed to gather data and not make contact with any natives. The asteroid exterior was a “blind” that has worked well until now, when humans are finally able to detect interstellar interlopers and make all kinds of speculations.

3. That an alien vessel passing through our Sol system and not giving us so much as a wave or a Hello is painful to our collective psyches, that the Universe remains indifferent to us even down to other intelligent life forms. This is similar to the reaction of Rama when it came through our system only to fuel up at our star and move on, with no intention or interest in talking to the residents of Sol 3.

Yes, Harry–that is why every airless solar system body we investigate, whether large or small, has the potential to shock us (as might heretofore-undiscovered moonlets [or other, even smaller objects] orbiting asteroids or planets). Not only would the outer solar system–especially the asteroid belt and Jupiter’s Trojan regions–be easy to hide in, but sunward of the Earth, small objects could easily escape detection. Also:

Interstellar expeditions to the solar system in the distant past (but even as recently as a few centuries ago) could have deliberately left behind instruments (like the Apollo EASEP and ALSEP stations left on the Moon, but more sophisticated and long-lived) to monitor and report on events in the solar system. Even still-active instruments or probes are possible; if their makers wanted them to remain undiscovered, they could easily be programmed to transmit back home (especially via laser) only when the Earth wouldn’t be positioned to accidentally “hear” the transmissions, and:

Such instrument packages–or probes with the same purpose–would be well-hidden even if they were placed (or landed) in plain sight on airless satellites or asteroids. The common attitude among researchers that “We could *never* be that lucky…such artifacts almost certainly ^aren’t^ there” may also ensure that any such things won’t be found (it’s easy to miss what one is convinced *isn’t* there to be found), at least until in-person visits to such worlds (or high-resolution robotic spacecraft surveys) are made, for other purposes. Now:

I don’t hold my breath for such discoveries to be made every time we fly by, orbit, or land on a “new” asteroid or comet with a robotic spacecraft, but we should always keep watch for such artifacts. Even Carl Sagan, when he saw what looked like an artificial light on Phobos in one of the first Mariner 9 closeup pictures of that Martian moon, asked the imaging team to run a computer analysis of the picture (to remove all single-bit errors). The bright spot went away, but a less open-minded scientist might not have even bothered to check into such an apparent anomaly because “it just couldn’t possibly be artificial.” What might we already have missed because of that attitude?

What If `Oumuamua WERE an interstellar spacecraft, but had ABSOLUTELY NO LNTEREST in us bipedal land-dwelling nuisances, but, instead, cared about the only REALLY intelligent species on the planet: The humpback whales! WAIT A MINUTE? Wasn.t this hashed out somewhere before?

Even more so if the red “end” is detachable. Remember, we have NO record of `Oumuamua PRIOR to closest passage to Earth. Who’s to say that the red “end” DID detach, headed for Earth, made a couple of orbits, checked to see if the humpback whales were still here, then took off, returned to the grey “cylinder”, and re-attached to it BEFORE we took our FIRST IMAGE of it!

Second Asteroid Detected With An Orbit That Will Take It Outside The Solar System

Astronomers have announced two more asteroids with hyperbolic orbits, following the enormous excitement generated by our first interstellar visitor last year. Unlike Oumuamua, both almost certainly originate within the Solar System. However, one is expected to escape the Sun’s gravity, providing a glimpse of how we come to get visitors from other stars. Moreover, the discoveries suggest more significant announcements could be on the way.

The discovery of Oumuamua, originally known as A/2017 U1, set off a frantic scramble to learn more about this precious insight into the galaxy beyond our Sun’s gravity well. Oumuamua’s strange features, such as its extreme length-to-width ratio and color, even sparked theories it could be an alien spaceship, although further study indicates this is unlikely.

Ten days after Oumuamua another object was detected with motion that indicates it will pass once around the Sun and never return. However, its announcement has only been made this week. In the case of A/2017 U7, careful study by astronomers suggests its origins lie in the outer reaches of the Solar System, known as the Oort Cloud, rather than around another star. Interactions with Jupiter’s gravity have tweaked its path, giving it enough energy to escape the Solar System. One day, in millions of years’ time, it could pay a close visit to some other star.

A/2017 U7 is much larger than Oumuamua at 13-59 kilometers (8-37 miles) across, and will make its closest approach to the Sun on September 10, 2019.

The announcement coincided with that of a third asteroid on a hyperbolic orbit, A/2018 C2. This asteroid also originates in the Oort Cloud, and got an extra kick of speed from the gravity of large planets, but in this case, astronomers expect the burst will be temporary, and further gravitational interactions will keep it orbiting the Sun.

Many comets have been observed with similar orbits. Some, like A/2018 C2, have further encounters that keep them in the Solar System. Others are more A/2017 U7-like and expected to escape. None are thought to have come from elsewhere, instead being Solar System objects given gravitational boosts.

Comets are easy to spot, however, with their long tails advertising their presence. To pick up an asteroid making such a rapid visit to the inner Solar System, and notice its extreme orbit, is much more of an achievement. This is why the latest announcements have astronomers excited, although it is still possible cometary activity will be seen as they get closer. Until six months ago we had not found a single asteroid with an orbit like this; now we have three. This proves new asteroid-tracking equipment is working well, and if any other interstellar visitors come our way, we are likely to find them.

An asteroid is about to embark on a very long voyage to interstellar space

Phil Plait from Bad Astronomy

March 6, 2018

A tweet by my colleague Ron Baalke alerted me to some interesting news. Astronomers have just announced the discovery of an asteroid that’s highly unusual: It’s on a hyperbolic orbit.

That’s a technical term for the shape of the orbit, which I’ll explain in a sec, but in more general terms it means the asteroid is not gravitationally bound to the Sun. Once it swings around and heads back out, it ain’t coming back.

It’ll be an interstellar asteroid.

If that sounds familiar, it may be because of the recent news about ‘Oumuamua, a rock that we know came from deep interstellar space, literally from another star. However, this newly discovered rock — called A/2017 U7 — is almost certainly an original member of our own solar system. How can that be?

By the way, only three hyperbolic asteroids are known: ‘Oumuamua, U7, and another recently discovered called A/2018 C2. That’s assuming these are asteroids; just because no activity is seen doesn’t mean there isn’t any. It could be faint, or it could switch on later. C2 gets closer to the Sun than U7 and may yet become active.

Lots of hyperbolic comets are known, mostly because objects from the Oort Cloud are far more likely to be cometary (with ice) than asteroidal (rock and metal). That’s why we’re still waiting to see if U7 and C2 show any activity. It’s likely they will given all this, but not certain.

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last eleven years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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